US20050110750A1 - Apparatus and method of processing signals - Google Patents
Apparatus and method of processing signals Download PDFInfo
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- US20050110750A1 US20050110750A1 US10/997,427 US99742704A US2005110750A1 US 20050110750 A1 US20050110750 A1 US 20050110750A1 US 99742704 A US99742704 A US 99742704A US 2005110750 A1 US2005110750 A1 US 2005110750A1
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
- G09G5/36—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators characterised by the display of a graphic pattern, e.g. using an all-points-addressable [APA] memory
- G09G5/39—Control of the bit-mapped memory
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0252—Improving the response speed
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2340/00—Aspects of display data processing
- G09G2340/16—Determination of a pixel data signal depending on the signal applied in the previous frame
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2360/00—Aspects of the architecture of display systems
- G09G2360/18—Use of a frame buffer in a display terminal, inclusive of the display panel
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3648—Control of matrices with row and column drivers using an active matrix
Definitions
- the present invention relates to an apparatus and method of processing signals, more particularly, to a signal processing apparatus using at least one memory to store a plurality of frame image data.
- a liquid crystal display device includes two substrates having a plurality of pixel electrode and a common electrode and a liquid crystal layer disposed between them. Such a liquid crystal display device applies certain voltage to the two electrodes to generate an electric field in the liquid crystal layer. And the liquid crystal display device controls transmittance of the light through the liquid crystal layer by adjusting the amplitude of the electric field. As a result, the liquid crystal display device implements desired images.
- a liquid crystal display device is one of flat panel displays, and particularly the liquid crystal display device having a switching element each a pixel is widely used.
- one frame represents a period that scans from one gate line to final gate line.
- one frame represents a period that scans from 1 to 768.
- the present invention provides a signal processing apparatus and method capable of storing three frame data using one frame memory, and also an image display apparatus having the signal processing apparatus.
- a signal processing apparatus includes a signal processing portion to receive a first clock and first to third image signals, and generate a second clock, and output corrected image signals with respect to compared results of the first to third image signals; and a frame memory connected to the signal processing portion, and to output the stored first and second image signals to the signal processing portion and to store the third image signals according to the second clock.
- a frequency of the second clock is higher than that of the first clock.
- the frame memory stores and outputs the first to third image signals during T/3 period (T: 1 frame).
- the first to third image signals are image signals during 1 frame period, respectively.
- the corrected image signals are one of overshoot and undershoot image signals.
- a frequency of the second clock is 1.5 times as high as that of the first clock.
- the signal processing portion includes a clock generating portion to receive the first clock, and generate the second clock and a third clock; a first write buffer to store the third image signals according to the third clock, and output the third image signals according to the second clock; a second write buffer to store and output the third image signals according to the third clock; and first and second read buffers to store the first and second image signals according to the second clock, and output the first and second image signals according to the third clock.
- the signal processing portion further includes a data correction portion to receive the first to third image signals, and output corrected image signals.
- a frequency of the third clock is lower than those of the first and second clocks, and a frequency of the second clock is high than that of the first clock.
- the first write buffer stores the third image signals during T period (T: 1 frame) according to the third clock, and outputs the third image signals during T/3 period according to the second clock.
- the second write buffer stores the third image signals during T period according to the third clock.
- the first and second read buffers store the first and second image signals during T/3 period according to the second clock, and output the first and second image signals during T period according to the third clock.
- a frequency of the second clock is 1.5 times as high as that of the first clock
- a frequency of the third clock is a 1 ⁇ 2 frequency of the first clock.
- the first and second read buffers are line memories, and the first and second write buffers are line memories.
- the first to third image signals are image signals during 1 frame period.
- the first write buffer stores the third image signals, and then outputs them after 2T/3 period.
- the second write buffer stores the third image signals, and then outputs them after T/3 period.
- the first read buffer stores the first image signals and then outputs them after T/3 period, and the second read buffer stores and outputs them at the same time T/3 period after storing operation of the first read buffer.
- the first and second read buffers, and the first and second write buffers output the first to third image signals at the same time, respectively.
- FIG. 1 is a block diagram illustrating a liquid crystal display device according to an embodiment of the present invention
- FIG. 2 is an equivalent circuit of one pixel in the liquid crystal display device according an embodiment of the present invention.
- FIG. 3 is a block diagram illustrating a signal processing apparatus according an embodiment of the present invention.
- FIG. 4 is a view illustrating read/write timing of a frame memory according an embodiment of the present invention.
- FIG. 5 is a view illustrating read/write timing of a buffer according an embodiment of the present invention.
- FIG. 6 is a timing diagram illustrating read/write data of a first read buffer according to an embodiment of the present invention.
- FIG. 7 is a timing diagram illustrating read/write data of a second read buffer according to an embodiment of the present invention.
- FIG. 8 is a timing diagram illustrating read/write data of a first write buffer according to an embodiment of the present invention.
- FIG. 9 is a timing diagram illustrating read/write data of a second write buffer according to an embodiment of the present invention.
- FIG. 1 is a block diagram of a liquid crystal display device according to an embodiment of the present invention
- FIG. 2 is an equivalent circuit of a pixel in the liquid crystal display device according to an embodiment of the present invention.
- the liquid crystal display device 100 includes a liquid crystal panel assembly 300 , a gate drive portion 400 , a data drive portion 500 , a gamma voltage generating portion 800 , and a signal control portion 600 .
- the liquid crystal panel assembly 300 includes gate lines G 1 -Gn, data lines D 1 -Dm, and a plurality of pixels arranged in a matrix. Each pixel has a switching element Q connected to the gate and data line, a liquid crystal capacitor Clc, and a storage capacitor Cst. The storage capacitor Cst may not need as required.
- the switching element Q is formed on a lower substrate 100 and has three terminal, for example, two terminals are connected the gate and data line, respectively and another terminal is connected to a pixel electrode 190 .
- the liquid crystal capacitor Clc represents a capacitor that a liquid crystal layer 3 is disposed between the pixel electrode 190 and a common electrode 270 .
- the common electrode 270 is formed on an upper substrate 200 .
- the common electrode 270 may be formed on the lower substrate 100 .
- the storage capacitor Cst represents a capacitor that a separate signal line (not shown) formed on the lower substrate 100 overlaps the pixel electrode 190 . Further, the storage capacitor Cst may form a capacitor that the pixel electrode 190 overlaps a previous gate line.
- the gamma voltage generating portion 800 generates two groups of gamma voltages, for example, one group has higher voltages and another group has lower voltages than a common voltage.
- the gamma voltage generating portion 800 includes resistors connected to each other and the number of the resistors depends on devices. Further, the gamma voltage generating portion 800 may have IC-typed element.
- the gate drive portion 400 includes a plurality of gate drivers and the gate drivers are connected to the gate lines.
- the gate driver portion 400 applies a gate signal to the gate lines in order to turn on and off the switching elements. Further, the gate drive portion 400 may be formed on the lower substrate 100 .
- the data drive portion 500 includes a plurality of data drivers and the data drivers are connected to the data lines.
- the data drive portion 500 applies a desired image signal to the data lines by selecting a certain gamma voltage from the gamma voltage generating portion 800 .
- the gate and data driver may form by attaching a TCP (Tape Carrier Package)(not shown) to the liquid crystal panel assembly 300 , or may be mounted on the lower substrate 100 , for example, COG (Chip On Glass).
- the signal control portion 600 generates control and timing signals and controls the gate drive portion 400 and the data drive portion 500 .
- the signal control portion 600 receives an input control signals (Vsync, Hsync, Mclk, DE) from a graphic controller (not shown) and an input image signal (R, G, B) and generates image signals R′, G′, B′, gate control signals CONT 1 and data control signals CONT 2 with respect to the input control signals and the input image signals. Further, the signal control portion 600 sends the gate control signals CONT 1 to the gate drive portion 400 and the data control signals CONT 2 to the data drive portion 500 .
- the gate control signals CONT 1 include STV informing start of one frame, CPV controlling an output timing of the gate on signal, OE informing an ending time of one horizontal line, etc.
- the data control signals CONT 2 include STH informing start of one horizontal line, TP or LOAD instructing an output of data voltages, RVS or POL instructing polarity reverse of data voltages with respect to a common voltage, etc.
- the data drive portion 500 receives the image signals R′, G′, B′ from the signal control portion 600 and outputs the data voltages by selecting gamma voltages corresponding to the image signals R′, G′, B′ according to the data control signals CONT 2 .
- the gate driver portion 400 applies the gate on signal according to the gate control signals CONT 1 to the gate lines and turns on the switching elements Q connected to the gate lines.
- the liquid crystal display device 100 has SXGA resolution (Clock frequency is 108 MHz) and 24 bit R, G, B data. It should be note that the clock frequency and the number of bit depends on the resolution of the display device.
- the image signals for nth frame Gn indicate the image signals for first frame
- the image signals for (n ⁇ 1)th frame Gn- 1 indicate the image signals for second frame
- the image signals for (n ⁇ 2)th frame Gn- 2 indicate the image signals for third frame.
- the signal processing apparatus 40 may be mounted in the signal control portion 600 in whole or in part.
- FIG. 3 is a block diagram of the signal processing apparatus 40 according to an embodiment of the present invention.
- the signal processing apparatus 40 includes a signal processing portion 42 and a frame memory 43 .
- Input and output terminals of the signal processing portion 42 correspond to input and output terminals of the signal processing apparatus 40 .
- the signal processing portion 42 includes a clock generating portion 44 , a first write buffer 45 , a first read buffer 46 and a second read buffer 47 that are connected to the clock generating portion 44 and the frame memory 43 , respectively, a second write buffer 48 connected to the clock generating portion 44 , and a data correction portion 49 connected to the first read buffer 46 , the second read buffer 47 and the second write buffer 48 .
- the clock generating portion 44 generates second and third clocks Clk 2 and Clk 3 with respect to an external first clock Clk 1 .
- the first clock Clk 1 has the frequency of 108 MHz.
- the second clock Clk 2 has the frequency of 162 MHz being about 1.5 times as high as the first clock Clk 1 .
- the third clock Clk 3 has the frequency of 54 MHz being about 1 ⁇ 2 of the first clock Clk 1 .
- the second clock Clk 2 is 3 times as high as the third clock Clk 3 .
- the clock generating portion 44 includes PLL circuit (not shown) for generating the second clock Clk 2 .
- the third clock Clk 3 may be generated by half dividing the first clock Clk 1 by a flip-flop.
- the first write buffer 45 writes the image signals for first frame Gn inputted from outside according to the third clock Clk 3 , and the image signals for first frame Gn is stored in the frame memory 43 according to the second clock Clk 2 .
- the second write buffer 48 stores the image signals for first frame Gn according to the third clock Clk 3 , and the stored image signals for first frame Gn is sent to the data correction portion 49 according to the third clock Clk 3 .
- the first read buffer 46 stores the image signals for third frame Gn- 2 stored in the frame memory 43 according to the second clock Clk 2 , and the image signals for third frame Gn- 2 is sent to the data correction portion 49 according to the third clock Clk 3 .
- the second read buffer 47 stores the image signals for second frame Gn- 1 from the frame memory 43 according to the second clock Clk 2 , and the stored image signals for second frame Gn- 1 is sent to the data correction portion 49 according to the third clock Clk 3 .
- the second write buffer 48 operates by synchronizing with the third clock Clk 3 and the first write buffer 45 and the first and second read buffers 46 and 47 operate by synchronizing the second and third clocks Clk 2 and Clk 3 .
- the first write buffer 45 and the first and second buffers 46 and 47 may implement by using FIFO (First-In-First-Out) or Dual Port RAM. Further, the second write buffer 48 may implement by using the FIFO or the Dual Port RAM.
- the FIFO and Dual Port RAM has a separated input and output terminals, and thus may input and output image data by synchronizing with a different clock frequency at the input and output terminals.
- the data correction portion 49 reads the image signals for first frame Gn from the second write buffer 48 , the image signals for second frame Gn- 1 from the second read buffer 47 , and the image signals for third frame Gn- 2 from the first read buffer 46 . Further, the data correction portion 49 compares the image signals for first, second and third frames Gn, Gn- 1 , Gn- 2 and outputs a corrected image signals according to the compared result.
- the data correction portion 49 may include a data comparing portion (not shown) that compares the image signals for first, second and third frames Gn, Gn- 1 and Gn- 2 and outputs image signals corresponding to the compared results, at least one Look-Up Table (LUT) (not shown) that stores corrected image signals with respect to the sections of the image signals for first, second and third frames Gn, Gn- 1 and Gn- 2 , and at least one modifier (not shown) that calculates corrected image signals with respect to the image signals from the data comparing portion.
- LUT Look-Up Table
- the frame memory 43 may include, for example, DDR SDRAM.
- the DDR SDRAM may implement read/write operation at rising and falling edges of clock, respectively.
- the frame memory 43 represents FM
- the first write buffer 45 represents WLM 1
- the second write buffer 48 represents WLM 2
- the first read buffer 46 represents RLM 1
- the second read buffer 47 represents RLM 2 .
- FIG. 4 is a timing diagram showing read/write operations in the frame memory according to an embodiment of the present invention.
- the image signals for first frame Gn are sent to the signal processing apparatus 40 from an external device (not shown) for a high period of Data Enable T.
- the image signals for first frame Gn (data_in) is inputted by synchronizing with the first clock Clk 1 and is inputted one data per a clock.
- one horizontal line data represents D 1 , D 2 , . . . , Dx and the data is 24 bit.
- the signal processing portion 42 writes the image signals in the frame memory 43 and reads the image signals from the frame memory 43 by synchronizing with the second clock Clk 2 .
- the signal processing portion 42 implements write/read operations of two image signals per a clock.
- a data processing speed of the signal processing apparatus 40 is 3 times as fast as that of the image signals of first frame Gn (data_in).
- the signal processing apparatus 40 may implement read/write operations during T/3 period.
- the signal processing portion 42 reads the image signals for third frame Gn- 2 from the frame memory 43 during T/3 period, and then reads the image signals for second frame Gn- 1 from the frame memory 43 during T/3 period, and then writes the image signals for first frame Gn in the frame memory 43 during T/3 period. Further, the signal processing portion 42 may read the image signals for second frame Gn- 1 from the frame memory 43 during T/3 period, and then read the image signals for third frame Gn- 2 from the frame memory 43 during T/3 period.
- FIG. 5 is a timing diagram showing read/write operations in the buffers 45 to 48 according to an embodiment of the present invention.
- the signal processing portion 42 reads the image signals for third frame Gn- 2 from the frame memory 43 during T/3 period, and then writes them in the first read buffer 46 (RLM 1 ). And the signal processing portion 42 reads the image signals for third frame Gn- 2 from the frame memory 43 during T period and sends them to the data correction portion 49 .
- the signal processing portion 42 writes the image signals for third frame Gn- 2 in the first read buffer 46 by synchronizing with the second clock Clk 2 and reads them by synchronizing with the third clock Clk 3 .
- the signal processing portion 42 reads the image signals for second frame Gn- 1 from the frame memory 43 during T/3 period, and writes them in the second read buffer 47 (RLM 2 ). And the signal processing portion 42 reads the image signals for third frame Gn- 1 from the frame memory 43 during T period and sends them to the data correction portion 49 .
- the signal processing portion 42 writes the image signals for second frame Gn- 1 in the first read buffer 46 by synchronizing with the second clock Clk 2 and reads them by synchronizing with the third clock Clk 3 .
- the signal processing portion 42 receives the image signals for second frame Gn from an external device (not shown) during T period, and writes them in the first write buffer 45 (WLM 1 ). And the signal processing portion 42 reads the image signals for first frame Gn from the first write buffer 45 during T/3 period and writes them to the frame memory 43 . The signal processing portion 42 writes the image signals for first frame Gn in the first write buffer 45 by synchronizing with the third clock Clk 3 and reads them by synchronizing with the second clock Clk 2 .
- the signal processing portion 42 receives the image signals for second frame Gn from an external device (not shown) during T period, and writes them in the second write buffer 48 (WLM 2 ). And the signal processing portion 42 receives the image signals for first frame Gn from the second write buffer 48 during T period and sends them to the data correction portion 49 .
- the signal processing portion 42 writes or reads the image signals for first frame Gn in the second write buffer 48 by synchronizing with the third clock Clk 3 and reads them by synchronizing with the second clock Clk 2 .
- timings of the image signals that are read from or written in the first and second read/write buffers 45 to 48 will be in detail described with reference to FIGS. 6 to 9 .
- FIG. 6 is a timing diagram showing read/write operations from or in the first read buffer 46 according to an embodiment of the present invention.
- the second clock Clk 2 has T period for writing the image signals for third frame Gn- 2 in the first read buffer 46 (RLM 1 ) and the third clock Clk 3 has 3T period for reading the image signals for third frame Gn- 2 from the first read buffer 46 (RLM 1 ).
- the image signals for third frame Gn- 2 (FM_data), for example, 24 bit image signals, are read from the frame memory 43 by synchronizing with rising and falling edges of the second clock Clk 2 .
- the image signals for third frame Gn- 2 processed in the first read buffer 46 (RLM 1 ) are 48 bit data that include odd and even data.
- This may be implemented by a plurality of Flip-Flops.
- the odd data of the image signals for third frame Gn- 2 is latched at a rising edge of the second clock Clk 2 and the even data of the image signals for third frame Gn- 2 is latched at a falling edge of the second clock Clk 2 .
- the latched odd data is delayed by 1 ⁇ 2 clock, and thus 48 bits data (RLM 1 :WRITE_data) is generated.
- the signal processing portion 42 When the signal processing portion 42 writes the image signals in the first read buffer 46 (RLM 1 ), it writes one data per a clock by synchronizing with the second clock Clk 2 . Therefore, the signal processing portion 42 may process the image signals by the same speed as the frame memory 43 . For example, the signal processing portion 42 may write one line data among the image signals for third frame Gn- 2 in the first read buffer 46 (RLM 1 ) during T/3 period.
- the signal processing portion 42 reads the image signals for third frame Gn- 2 from the first read buffer 46 (RLM 1 ) by synchronizing with the third clock Clk 3 , and then send them to the data correction portion 49 . Since the period of the third clock Clk 3 is 3T, one line data of the image signals for third frame Gn- 2 (RLM 1 :READ_data) synchronizing with the third clock Clk 3 is output during T period.
- FIG. 7 is a timing diagram showing read/write operations from or in the second read buffer 47 according to an embodiment of the present invention.
- timings of the image signals for second frame Gn- 1 that are processed in the second read buffer 47 (RLM 2 ) are the same as those processed in the first read buffer 46 (RLM 1 ).
- the signal processing portion 42 reads the image signals for second frame Gn- 1 from the frame memory 43 during T/3 period and writes them in the second read buffer 47 (RLM 2 ). Therefore, the descriptions of the second read buffer 47 (RLM 2 ) will be omitted.
- Gn- 2 is latched at a falling edge of the second clock Clk 2 . Then, the latched odd data is delayed by 1 ⁇ 2 clock, and thus 48 bits data (RLM 1 :WRITE_data) is generated.
- the signal processing portion 42 When the signal processing portion 42 writes the image signals in the first read buffer 46 (RLM 1 ), it writes one data per a clock by synchronizing with the second clock Clk 2 . Therefore, the signal processing portion 42 may process the image signals by the same speed as the frame memory 43 . For example, the signal processing portion 42 may write one line data among the image signals for third frame Gn- 2 in the first read buffer 46 (RLM 1 ) during T/3 period.
- the signal processing portion 42 reads the image signals for third frame Gn- 2 from the first read buffer 46 (RLM 1 ) by synchronizing with the third clock Clk 3 , and then send them to the data correction portion 49 . Since the period of the third clock Clk 3 is 3T, one line data of the image signals for third frame Gn- 2 (RLM 1 :READ_data) synchronizing with the third clock Clk 3 is output during T period.
- FIG. 7 is a timing diagram showing read/write operations from or in the second read buffer 47 according to an embodiment of the present invention.
- timings of the image signals for second frame Gn- 1 that are processed in the second read buffer 47 (RLM 2 ) are the same as those processed in the first read buffer 46 (RLM 1 ).
- the signal processing portion 42 reads the image signals for second frame Gn- 1 from the frame memory 43 during T/3 period and writes them in the second read buffer 47 (RLM 2 ). Therefore, the descriptions of the second read buffer 47 (RLM 2 ) will be omitted.
- FIG. 8 is a timing diagram showing read/write operations from or in the second read buffer 47 according to an embodiment of the present invention.
- the signal processing portion 42 receives the image signals for first frame Gn (data_in) by synchronizing with the first clock Clk 1 and writes them in the first write buffer 45 (WLM 1 ) by synchronizing with the third clock Clk 3 , and reads them from the first write buffer 45 (WLM 1 ) by synchronizing with the second clock Clk 2 .
- the signal processing portion 42 reads the image signals for first frame Gn from the first write buffer 45 (WLM 1 ) during T/3 period by synchronizing with the second clock Clk 2 . Therefore, the signal processing portion 42 may read the image signals during T/3 period. Since the image signals for first frame Gn (WLM 1 :READ_data) are 48 bits, the signal processing portion 42 transfers the image signals into 24 bits of the image signals and then sends the transferred image signals to the frame memory 43 . This may be implemented by using multiplexer (not shown). For example, the 48 bits of the image signals are connected to the input terminal of the multiplexer by 24 bits and the second clock Clk 2 is connected to a selector (not shown).
- FIG. 9 is a timing diagram showing read/write operations from or in the second write buffer 48 according to an embodiment of the present invention.
- the signal processing portion 42 substantially, simultaneously writes the image signals for first frame Gn in the first and second write buffers 45 and 48 (WLM 1 and WLM 2 ). Therefore, timings of the image signals for first frame Gn that are written in the second write buffer 48 (WLM 2 ) is the same as those that are written in the first write buffer 45 (WLM 1 ).
- the signal processing portion 42 While the signal processing portion 42 writes the image signals for first frame Gn in the second write buffer 48 (WLM 2 ), it reads the image signals for first frame Gn from the second write buffer 48 (WLM 2 ) by synchronizing with the third clock Clk 3 after T/3 period. And then, the signal processing portion 42 sends the image signals to the data correction portion 49 . Since a period of the third clock is 3T, one horizontal line data of the image signals for first frame Gn (WLM 2 :READ_data) is outputted during T period. The image signals for first, second and third frames Gn, Gn- 1 and Gn- 2 are synchronized with the third clock Clk 3 .
- the data correction portion 49 receives the image signals for first, second and third frames Gn, Gn- 1 and Gn- 2 from the first to second read buffer 45 and 46 (RLM 1 and RLM 2 ) and the second write buffer 48 (WLM 2 ). Further, the data correction portion 49 compares them and generates corrected image signals Gn′ according the compared results.
- the present invention may compare the image signals for 3 frames and generate corrected image signals according the compared results by using one frame memory.
- the present invention may reduce costs compared to that of using two or more frame memory and reduce the number of I/O pin of the signal processing apparatus. Further, the present invention may greatly reduce the mounting area that pluralities of frame memories occupy.
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Abstract
Description
- 1. Field of the Invention
- The present invention relates to an apparatus and method of processing signals, more particularly, to a signal processing apparatus using at least one memory to store a plurality of frame image data.
- 2. Description of the Related Art
- Generally, a liquid crystal display device includes two substrates having a plurality of pixel electrode and a common electrode and a liquid crystal layer disposed between them. Such a liquid crystal display device applies certain voltage to the two electrodes to generate an electric field in the liquid crystal layer. And the liquid crystal display device controls transmittance of the light through the liquid crystal layer by adjusting the amplitude of the electric field. As a result, the liquid crystal display device implements desired images. Such a liquid crystal display device is one of flat panel displays, and particularly the liquid crystal display device having a switching element each a pixel is widely used.
- Recently, as the user increasingly requires large-scale and high luminance product, it is greatly focused on quality of moving images. In particular, improvement of a response time is an important issue. For this purpose, there has been a technique to apply a data voltage more than a target voltage to the pixel electrode. This needs at least two frame memories capable of storing previous frame data and current frame data. Here, one frame represents a period that scans from one gate line to final gate line. For example, in case of XGA (1024×768), one frame represents a period that scans from 1 to 768.
- Therefore, it has been some problems that increase product costs and increase a mounting area of a control board.
- The present invention provides a signal processing apparatus and method capable of storing three frame data using one frame memory, and also an image display apparatus having the signal processing apparatus.
- In one embodiment, a signal processing apparatus includes a signal processing portion to receive a first clock and first to third image signals, and generate a second clock, and output corrected image signals with respect to compared results of the first to third image signals; and a frame memory connected to the signal processing portion, and to output the stored first and second image signals to the signal processing portion and to store the third image signals according to the second clock.
- A frequency of the second clock is higher than that of the first clock. The frame memory stores and outputs the first to third image signals during T/3 period (T: 1 frame). The first to third image signals are image signals during 1 frame period, respectively. The corrected image signals are one of overshoot and undershoot image signals. Further, a frequency of the second clock is 1.5 times as high as that of the first clock.
- Further, the signal processing portion includes a clock generating portion to receive the first clock, and generate the second clock and a third clock; a first write buffer to store the third image signals according to the third clock, and output the third image signals according to the second clock; a second write buffer to store and output the third image signals according to the third clock; and first and second read buffers to store the first and second image signals according to the second clock, and output the first and second image signals according to the third clock.
- The signal processing portion further includes a data correction portion to receive the first to third image signals, and output corrected image signals. A frequency of the third clock is lower than those of the first and second clocks, and a frequency of the second clock is high than that of the first clock. The first write buffer stores the third image signals during T period (T: 1 frame) according to the third clock, and outputs the third image signals during T/3 period according to the second clock. The second write buffer stores the third image signals during T period according to the third clock. The first and second read buffers store the first and second image signals during T/3 period according to the second clock, and output the first and second image signals during T period according to the third clock.
- A frequency of the second clock is 1.5 times as high as that of the first clock, and a frequency of the third clock is a ½ frequency of the first clock. The first and second read buffers are line memories, and the first and second write buffers are line memories. The first to third image signals are image signals during 1 frame period. The first write buffer stores the third image signals, and then outputs them after 2T/3 period. The second write buffer stores the third image signals, and then outputs them after T/3 period. The first read buffer stores the first image signals and then outputs them after T/3 period, and the second read buffer stores and outputs them at the same time T/3 period after storing operation of the first read buffer. The first and second read buffers, and the first and second write buffers output the first to third image signals at the same time, respectively.
- This application relies for priority upon Korean Patent Application No.2003-84535 filed on Nov. 26, 2003, the contents of which are herein incorporated by reference in its entirety.
- The above and other features and advantage points of the present invention will become more apparent by describing in detailed embodiments thereof with reference to the accompanying drawings, in which:
-
FIG. 1 is a block diagram illustrating a liquid crystal display device according to an embodiment of the present invention; -
FIG. 2 is an equivalent circuit of one pixel in the liquid crystal display device according an embodiment of the present invention; -
FIG. 3 is a block diagram illustrating a signal processing apparatus according an embodiment of the present invention; -
FIG. 4 is a view illustrating read/write timing of a frame memory according an embodiment of the present invention; -
FIG. 5 is a view illustrating read/write timing of a buffer according an embodiment of the present invention; -
FIG. 6 is a timing diagram illustrating read/write data of a first read buffer according to an embodiment of the present invention; -
FIG. 7 is a timing diagram illustrating read/write data of a second read buffer according to an embodiment of the present invention; -
FIG. 8 is a timing diagram illustrating read/write data of a first write buffer according to an embodiment of the present invention; and -
FIG. 9 is a timing diagram illustrating read/write data of a second write buffer according to an embodiment of the present invention. - Hereinafter the embodiments of the present invention will be described in detail with reference to the accompanied drawings.
-
FIG. 1 is a block diagram of a liquid crystal display device according to an embodiment of the present invention, andFIG. 2 is an equivalent circuit of a pixel in the liquid crystal display device according to an embodiment of the present invention. - As shown in
FIG. 1 , the liquidcrystal display device 100 includes a liquidcrystal panel assembly 300, agate drive portion 400, adata drive portion 500, a gammavoltage generating portion 800, and asignal control portion 600. - The liquid
crystal panel assembly 300 includes gate lines G1-Gn, data lines D1-Dm, and a plurality of pixels arranged in a matrix. Each pixel has a switching element Q connected to the gate and data line, a liquid crystal capacitor Clc, and a storage capacitor Cst. The storage capacitor Cst may not need as required. The switching element Q is formed on alower substrate 100 and has three terminal, for example, two terminals are connected the gate and data line, respectively and another terminal is connected to apixel electrode 190. The liquid crystal capacitor Clc represents a capacitor that aliquid crystal layer 3 is disposed between thepixel electrode 190 and acommon electrode 270. Thecommon electrode 270 is formed on anupper substrate 200. Further, thecommon electrode 270 may be formed on thelower substrate 100. The storage capacitor Cst represents a capacitor that a separate signal line (not shown) formed on thelower substrate 100 overlaps thepixel electrode 190. Further, the storage capacitor Cst may form a capacitor that thepixel electrode 190 overlaps a previous gate line. - The gamma
voltage generating portion 800 generates two groups of gamma voltages, for example, one group has higher voltages and another group has lower voltages than a common voltage. The gammavoltage generating portion 800 includes resistors connected to each other and the number of the resistors depends on devices. Further, the gammavoltage generating portion 800 may have IC-typed element. - The
gate drive portion 400 includes a plurality of gate drivers and the gate drivers are connected to the gate lines. Thegate driver portion 400 applies a gate signal to the gate lines in order to turn on and off the switching elements. Further, thegate drive portion 400 may be formed on thelower substrate 100. - The data drive
portion 500 includes a plurality of data drivers and the data drivers are connected to the data lines. The data driveportion 500 applies a desired image signal to the data lines by selecting a certain gamma voltage from the gammavoltage generating portion 800. The gate and data driver may form by attaching a TCP (Tape Carrier Package)(not shown) to the liquidcrystal panel assembly 300, or may be mounted on thelower substrate 100, for example, COG (Chip On Glass). - The
signal control portion 600 generates control and timing signals and controls thegate drive portion 400 and the data driveportion 500. - Now, it will be in detail explained about operation of the liquid crystal display device with reference to the accompanying drawings. The
signal control portion 600 receives an input control signals (Vsync, Hsync, Mclk, DE) from a graphic controller (not shown) and an input image signal (R, G, B) and generates image signals R′, G′, B′, gate control signals CONT1 and data control signals CONT2 with respect to the input control signals and the input image signals. Further, thesignal control portion 600 sends the gate control signals CONT1 to thegate drive portion 400 and the data control signals CONT2 to the data driveportion 500. The gate control signals CONT1 include STV informing start of one frame, CPV controlling an output timing of the gate on signal, OE informing an ending time of one horizontal line, etc. The data control signals CONT2 include STH informing start of one horizontal line, TP or LOAD instructing an output of data voltages, RVS or POL instructing polarity reverse of data voltages with respect to a common voltage, etc. - The data drive
portion 500 receives the image signals R′, G′, B′ from thesignal control portion 600 and outputs the data voltages by selecting gamma voltages corresponding to the image signals R′, G′, B′ according to the data control signals CONT2. Thegate driver portion 400 applies the gate on signal according to the gate control signals CONT1 to the gate lines and turns on the switching elements Q connected to the gate lines. - Generally, the liquid
crystal display device 100 receives 24 bit or 48 bit data, for example, 8 bit (Red)+8 bit (Green)+8 bit (Blue)=24 bit, from an external graphic controller. In this embodiment, assume that the liquidcrystal display device 100 has SXGA resolution (Clock frequency is 108 MHz) and 24 bit R, G, B data. It should be note that the clock frequency and the number of bit depends on the resolution of the display device. - For convenience, the image signals for nth frame Gn indicate the image signals for first frame, the image signals for (n−1)th frame Gn-1 indicate the image signals for second frame, and the image signals for (n−2)th frame Gn-2 indicate the image signals for third frame.
- Now, operation of the signal processing apparatus 40 according to the present invention will be in detail described with reference to
FIG. 3 . The signal processing apparatus 40 may be mounted in thesignal control portion 600 in whole or in part. -
FIG. 3 is a block diagram of the signal processing apparatus 40 according to an embodiment of the present invention. As shown inFIG. 3 , the signal processing apparatus 40 includes asignal processing portion 42 and aframe memory 43. Input and output terminals of thesignal processing portion 42 correspond to input and output terminals of the signal processing apparatus 40. - The
signal processing portion 42 includes aclock generating portion 44, afirst write buffer 45, afirst read buffer 46 and asecond read buffer 47 that are connected to theclock generating portion 44 and theframe memory 43, respectively, asecond write buffer 48 connected to theclock generating portion 44, and adata correction portion 49 connected to thefirst read buffer 46, thesecond read buffer 47 and thesecond write buffer 48. - The
clock generating portion 44 generates second and third clocks Clk2 and Clk3 with respect to an external first clock Clk1. As described the above, the first clock Clk1 has the frequency of 108 MHz. The second clock Clk2 has the frequency of 162 MHz being about 1.5 times as high as the first clock Clk1. The third clock Clk3 has the frequency of 54 MHz being about ½ of the first clock Clk1. The second clock Clk2 is 3 times as high as the third clock Clk3. Theclock generating portion 44 includes PLL circuit (not shown) for generating the second clock Clk2. The third clock Clk3 may be generated by half dividing the first clock Clk1 by a flip-flop. - The
first write buffer 45 writes the image signals for first frame Gn inputted from outside according to the third clock Clk3, and the image signals for first frame Gn is stored in theframe memory 43 according to the second clock Clk2. Thesecond write buffer 48 stores the image signals for first frame Gn according to the third clock Clk3, and the stored image signals for first frame Gn is sent to thedata correction portion 49 according to the third clock Clk3. - The
first read buffer 46 stores the image signals for third frame Gn-2 stored in theframe memory 43 according to the second clock Clk2, and the image signals for third frame Gn-2 is sent to thedata correction portion 49 according to the third clock Clk3. Thesecond read buffer 47 stores the image signals for second frame Gn-1 from theframe memory 43 according to the second clock Clk2, and the stored image signals for second frame Gn-1 is sent to thedata correction portion 49 according to the third clock Clk3. - The
second write buffer 48 operates by synchronizing with the third clock Clk3 and thefirst write buffer 45 and the first and second read buffers 46 and 47 operate by synchronizing the second and third clocks Clk2 and Clk3. Thefirst write buffer 45 and the first andsecond buffers second write buffer 48 may implement by using the FIFO or the Dual Port RAM. The FIFO and Dual Port RAM has a separated input and output terminals, and thus may input and output image data by synchronizing with a different clock frequency at the input and output terminals. - The
data correction portion 49 reads the image signals for first frame Gn from thesecond write buffer 48, the image signals for second frame Gn-1 from thesecond read buffer 47, and the image signals for third frame Gn-2 from thefirst read buffer 46. Further, thedata correction portion 49 compares the image signals for first, second and third frames Gn, Gn-1, Gn-2 and outputs a corrected image signals according to the compared result. - The
data correction portion 49 may include a data comparing portion (not shown) that compares the image signals for first, second and third frames Gn, Gn-1 and Gn-2 and outputs image signals corresponding to the compared results, at least one Look-Up Table (LUT) (not shown) that stores corrected image signals with respect to the sections of the image signals for first, second and third frames Gn, Gn-1 and Gn-2, and at least one modifier (not shown) that calculates corrected image signals with respect to the image signals from the data comparing portion. - The
frame memory 43 may include, for example, DDR SDRAM. The DDR SDRAM may implement read/write operation at rising and falling edges of clock, respectively. - Now, operation of the signal processing apparatus 40 according to the present invention will be in detail described with reference to FIGS. 4 to 9.
- In FIGS. 4 to 9, the
frame memory 43 represents FM, thefirst write buffer 45 represents WLM1, thesecond write buffer 48 represents WLM2, thefirst read buffer 46 represents RLM1, and thesecond read buffer 47 represents RLM2. -
FIG. 4 is a timing diagram showing read/write operations in the frame memory according to an embodiment of the present invention. - As shown in
FIG. 4 , the image signals for first frame Gn (data_in) are sent to the signal processing apparatus 40 from an external device (not shown) for a high period of Data Enable T. The image signals for first frame Gn (data_in) is inputted by synchronizing with the first clock Clk1 and is inputted one data per a clock. Herein, one horizontal line data represents D1, D2, . . . , Dx and the data is 24 bit. As described the above, thesignal processing portion 42 writes the image signals in theframe memory 43 and reads the image signals from theframe memory 43 by synchronizing with the second clock Clk2. Thesignal processing portion 42 implements write/read operations of two image signals per a clock. Since the second clock Clk2 is 1.5 times as high as the first clock Clk1, a data processing speed of the signal processing apparatus 40 is 3 times as fast as that of the image signals of first frame Gn (data_in). For example, the signal processing apparatus 40 may implement read/write operations during T/3 period. - The
signal processing portion 42 reads the image signals for third frame Gn-2 from theframe memory 43 during T/3 period, and then reads the image signals for second frame Gn-1 from theframe memory 43 during T/3 period, and then writes the image signals for first frame Gn in theframe memory 43 during T/3 period. Further, thesignal processing portion 42 may read the image signals for second frame Gn-1 from theframe memory 43 during T/3 period, and then read the image signals for third frame Gn-2 from theframe memory 43 during T/3 period. - Now, operation of the first and second read buffers 46 and 47, and the first and second write buffers 45 and 48 within the
signal processing portion 42 according to an embodiment of the present invention will be in detail with reference toFIG. 5 . -
FIG. 5 is a timing diagram showing read/write operations in thebuffers 45 to 48 according to an embodiment of the present invention. - The
signal processing portion 42 reads the image signals for third frame Gn-2 from theframe memory 43 during T/3 period, and then writes them in the first read buffer 46 (RLM1). And thesignal processing portion 42 reads the image signals for third frame Gn-2 from theframe memory 43 during T period and sends them to thedata correction portion 49. Thesignal processing portion 42 writes the image signals for third frame Gn-2 in thefirst read buffer 46 by synchronizing with the second clock Clk2 and reads them by synchronizing with the third clock Clk3. - Further, the
signal processing portion 42 reads the image signals for second frame Gn-1 from theframe memory 43 during T/3 period, and writes them in the second read buffer 47 (RLM2). And thesignal processing portion 42 reads the image signals for third frame Gn-1 from theframe memory 43 during T period and sends them to thedata correction portion 49. Thesignal processing portion 42 writes the image signals for second frame Gn-1 in thefirst read buffer 46 by synchronizing with the second clock Clk2 and reads them by synchronizing with the third clock Clk3. - Further, the
signal processing portion 42 receives the image signals for second frame Gn from an external device (not shown) during T period, and writes them in the first write buffer 45 (WLM1). And thesignal processing portion 42 reads the image signals for first frame Gn from thefirst write buffer 45 during T/3 period and writes them to theframe memory 43. Thesignal processing portion 42 writes the image signals for first frame Gn in thefirst write buffer 45 by synchronizing with the third clock Clk3 and reads them by synchronizing with the second clock Clk2. - Further, the
signal processing portion 42 receives the image signals for second frame Gn from an external device (not shown) during T period, and writes them in the second write buffer 48 (WLM2). And thesignal processing portion 42 receives the image signals for first frame Gn from thesecond write buffer 48 during T period and sends them to thedata correction portion 49. Thesignal processing portion 42 writes or reads the image signals for first frame Gn in thesecond write buffer 48 by synchronizing with the third clock Clk3 and reads them by synchronizing with the second clock Clk2. - Now, timings of the image signals that are read from or written in the first and second read/write buffers 45 to 48 will be in detail described with reference to FIGS. 6 to 9.
- Timings that the image signals are read or written from or in the
first read buffer 46 will be described with reference toFIG. 6 . -
FIG. 6 is a timing diagram showing read/write operations from or in thefirst read buffer 46 according to an embodiment of the present invention. As shown inFIG. 6 , the second clock Clk2 has T period for writing the image signals for third frame Gn-2 in the first read buffer 46 (RLM1) and the third clock Clk3 has 3T period for reading the image signals for third frame Gn-2 from the first read buffer 46 (RLM1). The image signals for third frame Gn-2 (FM_data), for example, 24 bit image signals, are read from theframe memory 43 by synchronizing with rising and falling edges of the second clock Clk2. Meanwhile, the image signals for third frame Gn-2 processed in the first read buffer 46 (RLM1) are 48 bit data that include odd and even data. This may be implemented by a plurality of Flip-Flops. For example, the odd data of the image signals for third frame Gn-2 is latched at a rising edge of the second clock Clk2 and the even data of the image signals for third frame Gn-2 is latched at a falling edge of the second clock Clk2. Then, the latched odd data is delayed by ½ clock, and thus 48 bits data (RLM1:WRITE_data) is generated. - When the
signal processing portion 42 writes the image signals in the first read buffer 46 (RLM1), it writes one data per a clock by synchronizing with the second clock Clk2. Therefore, thesignal processing portion 42 may process the image signals by the same speed as theframe memory 43. For example, thesignal processing portion 42 may write one line data among the image signals for third frame Gn-2 in the first read buffer 46 (RLM1) during T/3 period. - After the write operation, the
signal processing portion 42 reads the image signals for third frame Gn-2 from the first read buffer 46 (RLM1) by synchronizing with the third clock Clk3, and then send them to thedata correction portion 49. Since the period of the third clock Clk3 is 3T, one line data of the image signals for third frame Gn-2 (RLM1:READ_data) synchronizing with the third clock Clk3 is output during T period. - Next, timings that the image signals are read or written from or in the
second read buffer 47 will be described with reference toFIG. 7 . -
FIG. 7 is a timing diagram showing read/write operations from or in thesecond read buffer 47 according to an embodiment of the present invention. As shown inFIG. 7 , timings of the image signals for second frame Gn-1 that are processed in the second read buffer 47 (RLM2) are the same as those processed in the first read buffer 46 (RLM1). However, thesignal processing portion 42 reads the image signals for second frame Gn-1 from theframe memory 43 during T/3 period and writes them in the second read buffer 47 (RLM2). Therefore, the descriptions of the second read buffer 47 (RLM2) will be omitted. - Next, timings that the image signals are read or written from or in the
second read buffer 47 will be described with reference toFIG. 8 . Gn-2 is latched at a falling edge of the second clock Clk2. Then, the latched odd data is delayed by ½ clock, and thus 48 bits data (RLM1:WRITE_data) is generated. - When the
signal processing portion 42 writes the image signals in the first read buffer 46 (RLM1), it writes one data per a clock by synchronizing with the second clock Clk2. Therefore, thesignal processing portion 42 may process the image signals by the same speed as theframe memory 43. For example, thesignal processing portion 42 may write one line data among the image signals for third frame Gn-2 in the first read buffer 46 (RLM1) during T/3 period. - After the write operation, the
signal processing portion 42 reads the image signals for third frame Gn-2 from the first read buffer 46 (RLM1) by synchronizing with the third clock Clk3, and then send them to thedata correction portion 49. Since the period of the third clock Clk3 is 3T, one line data of the image signals for third frame Gn-2 (RLM1:READ_data) synchronizing with the third clock Clk3 is output during T period. - Next, timings that the image signals are read or written from or in the
second read buffer 47 will be described with reference toFIG. 7 . -
FIG. 7 is a timing diagram showing read/write operations from or in thesecond read buffer 47 according to an embodiment of the present invention. As shown inFIG. 7 , timings of the image signals for second frame Gn-1 that are processed in the second read buffer 47 (RLM2) are the same as those processed in the first read buffer 46 (RLM1). However, thesignal processing portion 42 reads the image signals for second frame Gn-1 from theframe memory 43 during T/3 period and writes them in the second read buffer 47 (RLM2). Therefore, the descriptions of the second read buffer 47 (RLM2) will be omitted. - Next, timings that the image signals are read or written from or in the
second read buffer 47 will be described with reference toFIG. 8 . -
FIG. 8 is a timing diagram showing read/write operations from or in thesecond read buffer 47 according to an embodiment of the present invention. As described the above, thesignal processing portion 42 receives the image signals for first frame Gn (data_in) by synchronizing with the first clock Clk1 and writes them in the first write buffer 45 (WLM1) by synchronizing with the third clock Clk3, and reads them from the first write buffer 45 (WLM1) by synchronizing with the second clock Clk2. - The
signal processing portion 42 reads the image signals for first frame Gn from the first write buffer 45 (WLM1) during T/3 period by synchronizing with the second clock Clk2. Therefore, thesignal processing portion 42 may read the image signals during T/3 period. Since the image signals for first frame Gn (WLM1:READ_data) are 48 bits, thesignal processing portion 42 transfers the image signals into 24 bits of the image signals and then sends the transferred image signals to theframe memory 43. This may be implemented by using multiplexer (not shown). For example, the 48 bits of the image signals are connected to the input terminal of the multiplexer by 24 bits and the second clock Clk2 is connected to a selector (not shown). 24 bits of odd data are outputted at a low level of the second clock Clk2 and 24 bits of even data are outputted at a high level of the second clock Clk2. Therefore, as shown inFIG. 8 , one data per ½ clock of the second clock Clk2 is sent to theframe memory 43. - Next, timings that the image signals are read or written from or in the
second write buffer 48 will be described with reference toFIG. 9 . -
FIG. 9 is a timing diagram showing read/write operations from or in thesecond write buffer 48 according to an embodiment of the present invention. As described the above, thesignal processing portion 42 substantially, simultaneously writes the image signals for first frame Gn in the first and second write buffers 45 and 48 (WLM1 and WLM2). Therefore, timings of the image signals for first frame Gn that are written in the second write buffer 48 (WLM2) is the same as those that are written in the first write buffer 45 (WLM1). - While the
signal processing portion 42 writes the image signals for first frame Gn in the second write buffer 48 (WLM2), it reads the image signals for first frame Gn from the second write buffer 48 (WLM2) by synchronizing with the third clock Clk3 after T/3 period. And then, thesignal processing portion 42 sends the image signals to thedata correction portion 49. Since a period of the third clock is 3T, one horizontal line data of the image signals for first frame Gn (WLM2:READ_data) is outputted during T period. The image signals for first, second and third frames Gn, Gn-1 and Gn-2 are synchronized with the third clock Clk3. - The
data correction portion 49 receives the image signals for first, second and third frames Gn, Gn-1 and Gn-2 from the first tosecond read buffer 45 and 46 (RLM1 and RLM2) and the second write buffer 48 (WLM2). Further, thedata correction portion 49 compares them and generates corrected image signals Gn′ according the compared results. - Therefore, the present invention may compare the image signals for 3 frames and generate corrected image signals according the compared results by using one frame memory. As a result, the present invention may reduce costs compared to that of using two or more frame memory and reduce the number of I/O pin of the signal processing apparatus. Further, the present invention may greatly reduce the mounting area that pluralities of frame memories occupy.
- The present invention has been described with reference to the embodiments. It is evident, however, that many alternative modifications and variations will be apparent to those having skill in the art in light of the foregoing description. Accordingly, the present invention embraces all such alternative modifications and variations as fall within the spirit and scope of the appended claims.
Claims (25)
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US9640123B2 (en) * | 2012-12-21 | 2017-05-02 | Beijing Boe Optoelectronics Technology Co., Ltd. | Display driving method using overlapping scan mode to reduce coupling effect |
US9978330B2 (en) | 2012-12-21 | 2018-05-22 | Boe Technology Group Co., Ltd. | Display driving method using overlapping scan mode with reduced coupling effect |
Also Published As
Publication number | Publication date |
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KR20050050885A (en) | 2005-06-01 |
JP2005157389A (en) | 2005-06-16 |
CN1674079A (en) | 2005-09-28 |
CN100410999C (en) | 2008-08-13 |
TW200527371A (en) | 2005-08-16 |
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